It's not uncommon for water that comes from a municipal supply to have ammonia in it. Use a water conditioner that detoxifies ammonia, such as prime. You will still test positive for ammonia on your API liquid test kit because it tests for total ammonia. Does your tank have fish in it, or are you doing a fishless cycle?

Thanks for the quick response. My tank has two fish in it. I add Stress Coat to treat my water but was unaware that ammonia would still show up. Thank you for letting me know this! It would have driven me crazy.

In theory then, once my tank has cycled, will ammonia still show up on my test kit in my tank? If it always shows up, what's the point in testing for it?

City water are often treated with chloramines, which is broken down to Ammonia & chlorine with dechlor. A good dechlor like Prime will bind both so they are not toxic.

The bound ammonia, however, is still available to the biofilter & will be converted to nitrates. Once you cycle the tank, any ammonia in the tap will be converted in a matter of hours, so your ammonia should read zero.

City water are often treated with chloramines, which is broken down to Ammonia & chlorine with dechlor. A good dechlor like Prime will bind both so they are not toxic.

The bound ammonia, however, is still available to the biofilter & will be converted to nitrates. Once you cycle the tank, any ammonia in the tap will be converted in a matter of hours, so your ammonia should read zero.